Set incoming edge thicknesses proportional to the number of samples in that node

[jbao]

I just read the story where you shared the thoughts and lessons learned when implementing this nice library (thanks for that, great read indeed). This issue is part of the future work that is mentioned in the article. I hope it's still relevant? I'll try to submit a PR soon;-)

[parrt]

thanks and thanks :) Yep, relevant, but I'm not positive it'll actually look good. Should be an easy thing to code so not a huge waste if not used. just set penwidth on edge labels proportional to num samples descending on that edge.